Question 147 of 833
KCNA Kubernetes Fundamentals Practice Question
You have a Deployment with image: myapp:v1. You update the image to myapp:v2 using 'kubectl set image deployment/myapp myapp=myapp:v2'. The rollout status shows 'Waiting for rollout to finish: 0 out of 3 new replicas have been updated...'. What is the most likely cause of this behavior?
⚠ Common exam trap
Many candidates assume a syntax error (Option A) or a Pod crash (Option B) when the real issue is a missing or inaccessible image, which is a common cause of stuck rollouts in Kubernetes.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The new image myapp:v2 does not exist or cannot be pulled from the registry
The rollout is stuck waiting for new replicas to become ready, which typically happens when the container image cannot be pulled. The message '0 out of 3 new replicas have been updated' indicates that the ReplicaSet is attempting to create Pods with the new image, but the Pods are failing to start. The most common cause is that the image tag 'myapp:v2' does not exist in the registry or cannot be accessed due to authentication or network issues, preventing the kubelet from pulling it.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The command syntax is incorrect; you should use 'kubectl set image deployment/myapp myapp:v2'
Why it's wrong here
The syntax 'kubectl set image deployment/myapp myapp=myapp:v2' is correct.
- ✗
The new Pods are crashing due to a missing command
Why it's wrong here
Crashing Pods would cause CrashLoopBackOff, but the rollout would still attempt to update replicas; however, the specific message '0 out of 3 new replicas have been updated' suggests the new Pods are not being created.
- ✗
The Deployment's update strategy is set to 'Recreate'
Why it's wrong here
With 'Recreate', old Pods are terminated before new ones are created, so the rollout should progress.
- ✓
The new image myapp:v2 does not exist or cannot be pulled from the registry
Why this is correct
If the image cannot be pulled, the new Pods will remain in ImagePullBackOff, preventing them from being counted as updated.
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Last reviewed: Jul 4, 2026
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